RFjackX is a 100% free, open-source terminal-based sub-GHz radio transceiver and audio-SDR suite built strictly for Linux Operating Systems. By utilizing standard laptop sound card infrastructure, it automates the passive capture of ambient radio frequencies through a microphone input jack and performs audio-modulation upconversion to transmit signals back out via a headphone socket using low-cost generic hardware components.
Developed by Unknownx007.
- Acoustic Sub-SDR Capture: Reads analog voltages arriving from a custom AUX antenna circuit, strips noise thresholds, and writes data to a structured 16-bit PCM
.wavtrack file. - Terminal Visualizer Core: Computes Root-Mean-Square (RMS) amplitude parameters dynamically from incoming chunks, rendering animated audio visualizer waves inside the console interface.
- Audio-Modulation Upconversion: Generates high-frequency square-wave tones matching stored binary pulse strings, transmitting voltage spikes out of the headphone output socket.
- Hardware Multiplication: The incoming audio voltage triggers the data pin of an attached transmitter module, converting the signal into a physical sub-GHz radio wave.
This tool utilizes audio-modulation upconversion protocols. It works natively on STATIC RF systems (old garage doors, wireless doorbells, ceiling fans, and legacy remote triggers).
It will NOT bypass modern rolling code matrices (KeeLoq), as used by contemporary vehicles, which automatically expire codes per click. This limitation makes the tool an exceptional educational resource for learning the difference between static and dynamic wireless security configurations.
To bridge the gap between your laptop sound card and sub-GHz frequencies, you can construct two independent receiver and transmitter circuits completely for free using an old pair of headphones or auxiliary (AUX) audio cables.
- 1x Laptop with a 3.5mm Headphone Jack and a 3.5mm Microphone Jack (or a combined TRRS audio splitter adapter).
- 2x Old/Broken AUX Audio Cables (or standard wired headphone cords).
- 1x FS1000A 433MHz Transmitter Module (The square board with 3 pins).
- 1x 433MHz Receiver Module (The long rectangular board with 4 pins).
This circuit captures ambient 433MHz electrical leakage and pipes it straight into your laptop's sound card recording channels.
[ Old AUX Cable ] [ 433MHz Receiver Board (Long Board) ]
+-------------------+ +--------------------------------------+
| Copper Wire 1 | -----------> | DATA Pin (Either of the two centers) |
| (Microphone Core) | | |
| Copper Wire 2 | -----------> | GND Pin |
| (Ground Shield) | +--------------------------------------+
+-------------------+
- Cut your first AUX audio cable in half to expose the inner core wires.
- Strip away the plastic insulation to expose the bare copper strands of the Microphone Signal line and the Ground Shield line.
- Wrap or twist the Microphone Signal copper wire directly around either of the two middle
DATApins of your 4-pin receiver module. - Wrap or twist the Ground Shield copper wire directly around the
GNDpin of your receiver module. - Plug the 3.5mm jack connector straight into your laptop's Microphone Input Port.
This circuit captures high-frequency audio voltage spikes from your laptop speaker lines and triggers the radio transmission chip.
[ Old AUX Cable ] [ FS1000A Transmitter Board (Square) ]
+-------------------+ +--------------------------------------+
| Copper Wire 1 | -----------> | DATA Pin |
| (Left/Right Core) | | |
| Copper Wire 2 | -----------> | VCC Pin |
| (Ground Shield) | | |
| | ------+----> | GND Pin |
| | | +--------------------------------------+
| [External 5V]* | ------+ *(Optional External Power Supply)
+-------------------+
- Cut your second AUX audio cable in half and strip the core lines to expose the bare copper wires.
- Separate the Audio Signal line (Left or Right speaker core) and the Ground Shield line.
- Wrap or twist the Audio Signal copper wire directly around the
DATApin of your 3-pin FS1000A transmitter module. - Wrap or twist the Ground Shield copper wire directly around the
GNDpin of your transmitter module. - Note: To power the transmitter's
VCCpin, you can jumper it directly to a 5V pin on an old USB cable plugged into your laptop, or attach a small 3V-5V battery. - Plug the 3.5mm jack connector straight into your laptop's Headphone Output Port.
Here is that circuit looks like:
# 1. Clone this competitive suite repository
git clone https://github.com/Unknownx007/RFjackX
cd RFjackX
# 2. Configure and isolate the python virtual environment
python3 -m venv .venv
source .venv/bin/activate
# 3. Pull required microservice modules securely
pip install -r requirements.txt
# 4. Initialize the command-line control panel
python3 rfjackx.py- Run the tool. The main selection menu will display instantly.
- Select Option 1 (Sniffer Mode). If you don't have the circuits built yet, select Option 2 (Internal Simulator Mode) to test the code.
- Watch the color-coded ASCII sound wave animate live on your screen. Press
Ctrl + Cto stop and save the.wavfile. - Go back to the main menu and select Option 2 (Transmit Mode). Hit
Enterto load the saved track, stream the raw voltage audio pulses out of your headphone jack, and re-draw the visualization waves line by line!
Distributed under the MIT License. See LICENSE for more details.